Copolymers of units i and ii

ABSTRACT

1. A METHOD FOR THE PRODUCTION OF FIBER AND FILM-FORMING AROMATIC POLYMERS WHOSE MOLECULAR CHAINS COMPRISE BENZENOLD GROUPS AND OXYGEN ATOMS, IN WHCIH A DIHALOGENOBENZENOID COMPOUND HAVING THE FORMULA   X-PHENYLENE-Y-PHENYLENE-X&#39;&#39;   IN WHICH X AND X&#39;&#39; ARE EACH A HALOGEN ATOM AND Y IS -SO2-, -SO-, -CO-, OR A RADICAL OF THE FORMULA -Y&#39;&#39;-A-Y&#34;- IN WHICH Y&#39;&#39; AND y&#34; EACH IS -SO2-, -SO- OR -CO- AND A IS A BIVALENT AROMATIC RADICAL HAVING BOTH VALENCIES LINKED TO CARBON ATOMS IS CAUSED TO REACT WITH A SUBSTANTIALLY EQUIVALENT AMOUNT OF AN ALKALI METAL HYDROXIDE BY THE DISPLACEMENT OF ALKALI METAL HALIDE IN A POLAR LIQUID WHICH IS AN IONIZING SOLVENT FOR ALKALI METAL PHENOXIDES AND IS STABLE UNDER THE REACTION CONDITIONS EMPLOYED, THE REACTION BEING CONCLUDED UNDER ANHYDROUS CONDITIONS AND AT A TEMPERATURE BETWEEN 150*C., AND 350*C.

Nov. 26, 1974 o. A. BARR E-TAL Re. 28, 252

AROIATIC POLYMERS FROM DIHALOGENOBEHZENOID COIPOUNDS DID ALKALI IETAI-HYDROXIDI Driginal Filed lay so, 1973 0 IO I Eye ATTORNEYS United StatesPatent 28,252 AROMATIC POLYMERS FROM DIHALOGENO- BENZENOlD COMPOUNDS ANDALKALI METAL HYDROXIDE Dennis Arthur Barr, Welwyu, and John BrewsterRose, Letchworth, England, assignors to Imperial Chemical IndustriesLtd., London, England Original No. 3,634,355, dated Jan. 11, 1972, Ser.No. 714,899, Mar. 21, 1968, which is a continuation-in-part ofapplication Ser. No. 580,290, Sept. 19, 1966. Application for reissueMay 30, 1973, Ser. No. 365,086 Claims priority, application GreatBritain, Sept. 24, 1965, 40,734/65; Jan. 31, 1966, 4,176/66, 4,177/66,4,178/66; Mar. 7, 1966, 9,764/66; Mar. 23, 1967, 13,891/67, 13,892/67;Mar. 13, 1968, 12,231/68 Int. Cl. C08g /00, 23/00, 25/00 U.S. Cl. 260-4910 Claims Matter enclosed in heavy brackets I: appears in the originalpatent but forms no part of this reissue specification; matter printedin italics indicates the additions made by reissue.

ABSTRACT OF THE DISCLOSURE Aromatic polymers containing benzenoid groupsand oxygen atoms in the polymer chains are made by the action of analkali metal hydroxide, on a dihalogenobenzenoid compound in which eachhalogen atom is activated by an inert electron-attracting group such as-SO When a bis-(4-halogenophenyl) sulphone is reacted with an alkalimetal hydroxide, the alkali metal salt of a4-(4halogenophenylsulphonyl)phenol is formed as a readily isolatedintermediate which polymerises in the presence or absence of solvent togive a polymer having repeating units of the structure This applicationis a continuation-in-part of our ap plication Ser. No. 580,290 filed onSept. 19, 1966.

This invention relates to the production of aromatic polymers andintermediates therefor.

According to the invention, aromatic polymers whose molecular chainscomprise benzenoid groups and oxygen atoms and substances polymerisableto give such polymers are produced by a method in which adihalogenobenzenoid compound having such halogen atom activated by aninert electron-attracting group is caused to react with a substantiallyequivalent amount of an alkali metal hydroxide by the displacement ofalkali metal halide in a polar liquid which is an ionising solvent foralkali metal phenoxides and is stable under the reaction conditionsemployed.

The halogen atoms in the dihalogenobenzenoid compound are preferablychlorine or fluorine. The fluorine derivatives generally are morereactive and enable the displacement of alkali metal halide to becarried out more quickly, but are more expensive. Bromine derivativesare also relatively expensive and although they resemble the chlorinederivatives in performance they would seem to otter no advantages.Iodine derivatives are generally less suitable.

Any dihalogenobenzenoid compound or mixture of dihalogenobenzenoidcompounds is suitable for the invention provided the two halogen atomsare linked to benzene rings which have an electron-attracting group,preferably ortho or para to the halogen atom. The dihalogenobenzenoidcompound can have the halogen atoms linked to the same benzenoid ring ora difi'erent benzenoid rings so long as each is activated by anelectronattracting group.

An electron-attracting group inert under the conditions of the reactioncan be used as the activating group in these compounds. The morepowerful electron-attracting groups give the highest reaction rates andare therefore preferred. Electron-donating groups should also be absentfrom the same benzenoid ring as the halogen. It may be a univalent groupthat activates one or more halogen atoms in the same ring, for example anitro, phenylsulphonyl, alkylsulphonyl, cyano, tritiuoromethyl ornitroso group, or heteronitrogen as in pyridine; or it may be a bivalentgroup that can activate halogen atoms in two different rings, forexample a sulphone, sulphoxide, azo, carbonyl, vinylene, vinylidene,tetrafiuoroethylene or organic phosphine oxide group; or it may be abivalent group that can activate halogen atoms on the same ring, as inthe case of difluorobenzoquinone and 1,4-, 1,5- or1,S-difluoroanthraquinone.

In particular, the dihalogenobenzenoid compound may have the formula inwhich X and X are conveniently the same but may be different and arehalogen atoms, and Y is 40 SO or CO- or a radical of the formula YI AYII in which Y and Y" may be the same or different and each is SO SO orCO and A is a bi-' valent organic radical, which may be aliphatic,aromatic or heterocyclic and has both valencies linked to carbon atoms.For example A may be a bivalent aromatic radical derived from benzene, afused-ring aromatic hy drocarbon containing not more than two aromaticrings (for example naphthalene, indene, fiuorene or dibenzofuran), or acompound of the formula in which Z is a direct link, O, S-, SO CO, abivalent hydrocarbon or substituted hydrocarbon radical (e.g. alkylene,alkylidene or a bivalent cycloaliphatic or aromatic radical), or aresidue of an organic diol (i.e. the bivalent radical obtained byremoving the hydrogen atoms from the two hydroxy groups). The halogenatoms in the dihalogenbenzenoid compounds are preferably in the paraposition to the bridging group Y, because the essentially all-parapolymers that can be made from them have better physical properties asthermoplastic materials.

Lower alkyl, alkoxy or alkylthio groups may be present as substituentson any of the aromatic rings but are preferably absent from thehalogen-bearing rings and are also preferably absent altogether when thearomatic polymer is required to be stable at high temperatures.

If desired the polymers can be prepared from mixtures of two or moredihalogenobenzenoid compounds, and these may contain differentelectron-attracting groups.

It has been found that polymers having desirable physical properties,especially a high softening point, may be made by a method as describedabove in which a bis- (halogenophenylsulphonyl) benzenoid compound,alone or together with another dihalogenobenzenoid compound is caused toreact with an alkali metal hydroxide by the displacement of alkali metalhalide. In particular the bis-(halogenophenylsulphonyl) benzenoidcompound may have the formula [X--C H -SO ARSO C H X] rSOz C H4X inwhich X is a halogen atom and Ar is a bivalent aromatic radical derivedfrom benzene, biphenyl, terphenyls, or a fused-ring aromatic hydrocarboncontaining not more than three aromatic rings (for example naphthalene,indene, fluorene or dibenzofuran).

The halogen atoms are preferably para to the sulphone groups, althoughat least some may be ortho.

The other dihalogenobenzenoid compound that may be copolymerised withthe bis-(halogenophenylsulphonyl) benzenoid compound may be any of thosedescrlbed above and in particular may conveniently be a bis-(4-halogenophenyl) sulphone.

The alkali metal cation associated with the hydroxide anion isconveniently potassium or sodium. Displacement of alkali metal halideoften occurs more readily if the potassium cation is present in thereagent used, but the weight (and usually the price) per mole of apotass1um compound is higher than for the corresponding sodium compound.Some or all of the alkali metal cation in the reagent may be replaced byan organic onium cation having a positively charged heteroatom (forexample a quaternary ammonium cation such as tetramethylammonium) stableunder the conditions of the reaction, and the term alkali metal salt asused herein is deemed to refer also to salts containing such oniumcations.

In the reaction of the invention, one mole of the dihalogenobenzenoidcompound is used for two moles of the alkali metal hydroxide; i.e. thereagents are used in substantially equivalent amounts. Should one of thereagents suffer some decomposition or otherwise be lost from thereaction mixture it may be added initially in slight excess.

Suitable polar liquids for the reaction include: the lower dialkyl andcyclic alkylene sulphoxides and sulphones (e.g. dimethyl sulphoxide andl,l-dioxothiolan), [nitriles (e.g. benzonitrile),] diaryl ketones (e.g.benzophenone), diaryl sulphoxides and sulphones, ethers (e.g. dioxane,diethylene glycol dimethyl ether, diphenyl ether, methoxyphenyl ethers),non-olefinic tertiary alcohols (e.g. t-butanol), and water. Mixtures ofsuch substances may conveniently be used, e.g. when one or morecomponents of the mixture would otherwise be solid at the reactiontemperature. The liquid (or mixture of liquids) should preferably be asolvent also for the dihalogenobenzenoid compound and preferably alsofor the alkali metal hydroxide. The amount of the liquid is relativelyunimportant provided it is sufficient to dissolve alkali metal salts ofphenols produced in the reaction and is not too large to be economicallydisadvantageous. The total amount of solvent used is desirablysufiicient to ensure that none of the starting materials are in thesolid state in the reaction mixture. The liquid initially present in thereaction medium need not be the same as that present during the finalformation of the polymer. The original liquid may be allowed to remainduring the reaction with the subsequent addition of any desiredsolvents, or it may be removed, e.g. by distillation.

Changing the liquid reaction medium may be convenient as it allows theinitial use of liquids that would be less suitable for the final stages,being for example inconveniently volatile or unstable at polymerisationtemperatures or incapable of dissolving the resultant polymer to thedesired extent. For example, dimethyl sulphoxide is a convenient solventbut cannot be used at such high temperatures as l,l-dioxothiolan (cyclictetramethylene sulphone) which may therefore be substituted for itduring the reaction.

The liquid reaction medium need not contain any solvent for polymer ofhigh molecular weight even at the later stages of the reaction, althoughif it does not the product is of relatively low molecular weight unlessthe final stage of polymerisation is carried out in the melt; this maybe explained if the molecular chains of the polymer cease to grow in thesolid state.

For the production of low polymer, the polar liquid may conveniently bewater or a mixture of water and another liquid or liquids stable to heatunder alkaline conditions. The dihalogenobenzenoid compounds aregenerally immiscible with water and the reaction mixture thereforeusually consists of two phases. Vigorous stirring and the use of asuitable emulsifier are then helpful in maximising the interfacial areaand hence reaction rate.

The rate of polymer formation in the reaction of the invention riseswith rise of temperature and below 200 C. is usually uneconomically slow(although lower temperatures can be used e.g. with bis-(4-fluorophenyl)sulphone). It may however be advantageous to preheat the reactionmixture between C. and 200 C, until inorganic hydroxide anions are nolonger present and then raise the temperature to produce the polymer.Temperatures up to 400 C. may be employed, and 250350 C. is usuallyconvenient.

The reaction should initially be carried out under pressure if necessaryto prevent the escape of dihalogenobenzenoid compound and any volatilesolvent or cosolvent. Heating in vacuum may however be desirable at alater stage to remove unwanted solvents, e.g. dimethyl sulphoxide whichdecomposes at the temperatures require to produce high polymer e.g. frombis-(4-chlorophenyl) sulphone.

The vessel used should be made of or lined with a material that is inertto alkali metal hydroxides and also to alkali metal halides under theconditions employed. For example, glass is unsuitable as it tends toreact with hydroxide anion at high temperatures, upsetting thestoichiometry of the polymerisation and contaminating the product withsilicate. Some grades of stainless steel undergo surface crazing atthese temperatures in the presence of alkali metal halide, and vesselsmade of or lined with titanium or nickel or an alloy thereof or somesimilarly inert material would be preferable.

The polymerisation must be concluded under substantially anhydrousconditions to obtain products of high molecular weight. Water is formedin the reaction when an alkali metal hydroxide is used, and must then beremoved, conveniently by distillation, e.g. direct or by azeotropicdistillation. Any inert volatile liquid that forms an azeotropic mixturewith water may be used; benzene, xylene and halogenated benzenes areconvenient examples. This liquid need not itself be thoroughly removedafter all the water has gone.

It is often advantageous to keep the temperature below 150" C.(preferably at about l0()-140 C.) until all water has been removed, andthen to conclude the reaction at a temperature between 150 C. and 350 C.

The reduced viscosity of the polymer is desirably at least 0.3 (measuredat 25 C. at 1% in a solvent such as dimethyl formamide) if it is toserve for structural purposes.

To neutralise any reactive oxygen-containing anions, a reagent thereformay be introduced at the termination of the polymerisation. Reactivemonofunctional halides, for example methyl chloride, are particularlysuitable.

It has been found that an alkali metal salt of a 4-(4-halogenophenylsulphonyl)phenol or 4-(4 halogenobenzoyl)phenol and hencethe phenol itself are surprisingly readily obtained by the action of analkali metal hydroxide on a bis-(4-halogenophenyl) sulphone or ketone ina polar liquid which is an ionising solvent for the phenoxide and isstable under the conditions employed. Very little salt ofbis-(4-hydroxyphenyl) sulphone or ketone is formed, except in thepresence of excess alkali at high temperatures, because the secondhalogen atom in the bis- (4-halogenophenyl) sulphone or ketone isunexpectedly much less susceptible than the first to alkalinehydrolysis, and the desired salt of a 4-(4-halogenophenylsulphonyl)phenol or 4-(4-halogenobenzoyl) phenol can be isolated. [in excellentyield] Such salts in the solid state are novel and have been found to bevaluable intermediates for the production of aromatic polymers, themolecular chains of which comprise para-phenylene groups, oxygen atoms,and sulphone or ketone groups. When such a salt is heated at or aboveits melting point in the substantial absence of any diluent reactiveunder the conditions employed, polymer of high molecular Weight can beobtained with the elimination of alkali metal halide. The startingmaterial need not consist of a pure reagent but may comprise suchmaterials mixed with each other and/or mixed with some preformed lowpolymer.

The reaction to produce this polymerisable salt may be carried out attemperatures up to 200 C. but is preferably carried out below 150 C.because above this temperature some polymer or some alkali metal salt ofthe bisphenol or both may be formed. Temperatures above room temperatureand preferably above 60 C. are desirable for the reaction to occur at aneconomic rate. With a liquid in which both starting materials aresoluble, 100-l40 C. is generally convenient although lower temperaturescan readily be used with bis-(4-fluorophenyl) sulphone. However, withwater alone (which is not a solvent for the dihalogenobenzenoidcompound), temperatures above 150 C. are convenient so that thedihalogenobenzenoid compound is molten.

The alkali metal salt of the phenol is initially obtained dissolved inthe reaction medium and is preferably isolated directly, although forthe purpose of purification it may be more convenient in some cases toacidity and then isolate the free phenol. This can be converted backinto an alkali metal salt by treatment with a suitable base (e.g. analkali metal hydroxide or alkoxide).

A 4-(4-halogenophenylsulphonyl)phenol or 4-(4-halogenobenzoyl)phenol isa useful product in its own right, possessing a halogen atom as well asthe phenolic group, and can serve as a valuable chemical intermediate.For example the halogen atom can be replaced by amino or substitutedamino groups giving a wide variety of materials.

The polymeric products of low molecular weight which may be produced bythe method of the invention e.g. those formed in the presence of wateror at temperatures below 200 C. also may find industrial uses directly,for example as sizes and finishes or as lubricant additives or thickenerfor non-aqueous liquids. Products with a preponderance of halogenend-groups or of anionic oxygcn-containing end-groups may be prepared byemploying a slight excess of the dihalogenobenzoid compound or of thealkali metal hydroxide respectively. The anionic endgroups may of coursebe converted into phenolic groups by acidification.

The low polymers are also useful as intermediates for the production ofvarious high polymers. A low polymer with predominantly anionicend-groups, for example, can react with a benzenoid compound containingat least three activated halogen atoms to give a thermoset material.Free phenolic end-groups may be linked further in conventional manner,e.g. with diisocyanates.

If the stoichiometry of the initial reaction is carefully preserved, sothat activated halogen end-groups and anionic oxygen-containingend-groups are present in approximately equal numbers in the lowpolymers, these can be converted (like the alkali metal salts of thehalogenophenols described above) directly into thermoplastic highpolymers by heating at 200-400 C. (preferably 250- 350" C.) in thesubstantial absence of water or any other liquid diluent reactive underthe conditions employed. This reaction is conveniently carried out in anextruder.

The alkali metal halide resulting from the initial reaction with thedihalogenobenzenoid compound need not be removed before the subsequentanhydrous heating; together with further alkali metal halide formed inthe latter step it can all be removed from the resultant high polymer byany suitable means. For example, it can be extracted from the highpolymer using water, or the polymer itself can be dissolved in astrongly polar organic solvent (for example dimethyl formamide,l-methyl-Z-oxopyrrolidine, dimethyl sulphoxide, 1,1-dioxothiolan ornitrobenzene) and then reprecipitated by addition to a liquid such aswater which is miscible with the polymer solvent but itself anon-solvent for the polymer.

When the polymer is formed in solution, a convenient procedure is to addthe reaction mixture (which may be decanted or filtered from solidalkali metal halide) to an excess of a liquid which is miscible with thereaction solvent but in which the polymer is insoluble. If the reactionsolvent is water-miscible, or is miscible with a liquid in whichresidual alkali metal halide also dissolves, the polymer can thus beobtained in one step. Otherwise, as for example if the reaction mixtureis poured into methanol, the precipitated polymer initially containsalkali metal halide which can subsequently be washed out with water.

It has also been found that products having especially desirablephysical properties may be made by a method as described above in whichan alkali metal salt of a 4- (4-halogenobenzoyl)phenol is copolymerizedwith an alkali metal salt of a 2-(4-halogenobenzoyl)phenol or an alkalimetal salt of a 4 4 halogenophenylsulphonyl) phenol by the displacementof alkali metal halide. The physical properties of these polymers areclosely dependent on their crystallisation characteristics, e.g. degreeof crystallinity, crystal form, rate of crystallisation and meltingpoint. The all-para polyketone having repeating units of the Formula Iis a highly crystalline and rather intractable material, and thepresence of repeating units of the Formula II or III (III) in thecopolymers made according to the invention correspondingly reduces thetendency of the products to crystallise and also their melting points.

The polymerisations are preferably carried out in di methyl sulphonesolution at ZOO-250 C. in the absence of water and oxygen.Polymerisations in l,l-dioxothiolan solution at 240 C. tend to yieldpolymers of low molecular weight. Polymerizations in the absence ofsolvents at 320340 C. tend to form insoluble material; they may alsoisomerise units II into the para configuration I thus allowingcopolymers of the invention to be produced from monomer units II alone.

The present invention provides a means of controlling the crystallinityof aromatic polymers the chains of which comprise para-phenylene groups,oxygen atoms and carbonyl groups by replacing some of the para-phenylenegroups by ortho-phenylene groups and/ or replacing some of the carbonylgroups by sulphonyl groups; thus it is possible by replacing apredetermined proportion of such groups to adjust the crystallisationcharacteristics of the various products to give the physical propertiesmost suitable for particular purposes.

Tables 1 and 2 show the structures of examples of copolymers prepared bypolymerisations according to the invention in which both monomers wereinitially present in the reaction mixture, in comparison with thehomopolymers of each monomer.

7 TABLE 1.COPOLYMERS OF UNITS I AND II Ratio of I to II: Structure asmade 20/80 Amorphous.

35/65 Crystalline.

100/0 Crystalline M.P. 312 C. /100 Crystalline M.P. 338 C.

As made i.e. not after any annealing treatment likely to increasecrystallinity.

Crystallinity was detected by X-ray diffraction. Melting points weredetermined using a Perkin-Elmer differential scanning calorimeter on amg. sample With a heating rate of 16 deg. C./min. and are corrected bycalibration.

TABLE 2.-COPOLYMERS OF UNITS I AND III Ratio of I to II: Structure asmade" 0/100 Amorphous.

/50 Crystalline M.P. 295 C. 63/35 Crystalline.

/0 Crystalline M.P. 338 C.

The crystal forms exhibited by these copolymers are very similar to thatof poly(4,4'-diphenylene ether ketone) and, as reported in Dutchapplication 6408130, the regular alternating copolymer Q- Q -Q Q- J.

is almost certainly amorphous. Hence, the copolymers made by the presentinvention are thought to contain poly(4,4-diphenylene ether ketone)blocks.

Random copolymers may be readily obtained by slowly feeding the alkalimetal salt of the 2-(4-halogenobenzoyl)phenol or 4 (4halogenophenylsulphonyl)phenol into a reaction mixture which initiallycontained only the alkali metal salt of the 4-(4 halogenobenzoyl)phenol.Crystalline random copolymers, prepared in this way, generally havelower melting points than the block copolymers of the same composition.

Two types of copolymer are of major interest:

(a) Crystalline (random or block) copolymers with M.P. 250-300 C. forapplication as thermoplastic, fibreforming or film-forming materials.

(b) Copolymers which are amorphous as made but which crystallise onannealing or on nucleation, e.g. with poly-(4,4'-diphenylene etherketone). Such polymers may be cast into films or spun into fibres fromthe solutions in which they are prepared or may be isolated as amorphouspolymers and processed as such in the manner customary, e.g. forpolyethylene terephthalate films and fibres. Among the copolymers thatmay exhibit this behaviour are random copolymers or block copolymerswithin the approximate composition ranges II/I=20/80 and III/I=35/65 to50/50.

The following examples illustrate the invention.

EXAMPLE 1 Bis-(4-chlorophenyl) sulphone (14.36 g.; 0.05 mole), aqueous43.6% w./w. potassium hydroxide solution (12.88 g.; 0.10 mole KOH), and1,1-dioxothiolan (100 cm. were stirred vigorously under nitrogen at C.for 4 hours in a vessel fitted with a reflux condenser. Xylene (15 cm?)was then added, the reflux condenser was replaced by a Dean & Starkapparatus, and the mixture was boiled until all water (about 7 cm. wasremoved azeotropically (this took about 3 hours). Xylene was thendistilled off and the temperature of the reaction vessel was raised to240 C. After 7 hours the product was cooled to about C. and a stream ofmethyl chloride was passed through the vessel for about 10 minutes. Thesolution in the reaction vessel was then decanted from solid potassiumchloride through a sintered glass filter into ethanol (1 dmfi) withvigorous stirring. The precipitated polymer was washed several timeswith water and with ethanol and dried overnight at 100 C. in highvacuum.

A fibre could be drawn from the molten polymer.

EXAMPLE 2 Polymers may similarly be obtained as in Example 1 from his (4fiuorophenyl) sulphone, bis (4 chlorophenyl) sulphoxide, 4,4dichlorobenzophenone, 4,4- bis (4-chlorophenylsulphonyl)biphenyl, and4-(4-chlorophenylsulphonyl phenoxy-4'-chlorobenzophenone.

EXAMPLE 3 Bis-(4-chlorophenyl) sulphone (14.35 g.; 0.05 mole), aqueouspotassium hydroxide solution (12.88 g.; 0.10 mole of KOH) and dimethylsulphoxide (100 cm?) were stirred together in a stainless steel reactionvessel under a blanket of nitrogen for 24 hours at 100 C. Benzene (140cm?) was added and water (7 cm?) was removed as benzene-water azeotropeand then most of the benzene was removed by distillation.

1,1-dioxothiolan (100 cm. was added and dimethyl sulphoxide wasdistilled off at 50 C. under reduced pressure (1.5 torr). When thedimethyl sulphoxide had been removed, the mixture was stirred undernitrogen at 220 C. for 24 hours, cooled, and poured into ethanol. Theprecipitated product was washed with ethanol and water and dried toyield a polymer (11.4 g.) of reduced viscosity 0.10 at 1% in dimethylformamide at 25 C.

EXAMPLE 4 Bis-(4-chlorophenyl) sulphone (287 g.; 1 mole), potassiumhydroxide (112 g.; 2 moles) and water (1.7 dmfi) were shaken in astainless steel autoclave for 18 hours at 195200 C. The product wascooled and added to water (5 dmfi) when some solid was formed. Dilutesulphuric acid was added until the pH was below 2.0 and more solid wasprecipitated. The whole was extracted with diethyl ether (2 dmfi), afterwhich a solid remained suspended in the aqueous phase. This solid wasfiltered off, washed with water and dried to give a polymer (12 g.)shown by infra-red spectroscopy to contain units of the formulaMonomeric material was isolated from the ethereal phase as follows.Potassium hydroxide solution (1.0 N, 2 dm?) was added to extractphenolic material from residual bis-(4-chlorophenyl) sulphone (of which0.15 mole was recovered). The aqueous alkaline solution was thenacidified with concentrated hydrochloric acid to precipitate a mixtureof phenolic material g.) which separated as a gum. This was digestedwith hot chloroform (0.75 dmn'f) leaving a residue ofbis-(4-hydroxyphenyl) sulphone (71 g.; 0.28 mole) identified by infraredspectroscopy. The solution was evaporated to yield 4 (4chlorophenylsulphonyl) phenol (99 g.; 0.37 mole) identified by infra-redspectroscopy.

EXAMPLE 5 The rate of hydrolysis of bis-(4-chlorophenyl) sulphone (14.36g.; 0.05 mole) in the presence of 45% w./w. aqueous potassium hydroxide(26 g.; 0.20 mole KOH) in solution in dimethyl sulphoxide 100 cm?) wasstudied at 100 C., 120 C. and 140 C. The extent of hydrolysis wasmeasured by gravimetric estimation of chloride ion at various reactiontimes. In FIG. 1 of the accompanying drawings, the results are presentedas a graph in which the abscissa is the reaction time in hours and theordinate is the amount of chloride ion as a percentage of the totalamount of chlorine substituent in the bis-(4-chlorophenyl) sulphone.

At 140 C., complete hydrolysis was occurring. At 120 C. the two chlorinesubstituents were clearly being hydrolysed at different rates, and at100 C. hydrolysis beyond the half-way stage was very slow. The secondchlorine substituent was hydrolysed only at about one-hundredth the rateof the first. In this experiment there were two liquid phases presentinitially but only one phase during the latter part of the hydrolysis.

EXAMPLE 6 The experiment described in Example 5 was repeated using onlytwo molar equivalents of potassium hydroxide. Two liquid phases werepresent throughout. In FIG. 2 of the drawings, where the abscissa andordinate are as in FIG. 1, the results show that the removal of thechlorine substituent from potassium 4-(4chlorophenylsulphonyl)phenoxide, either by formation of polymer or byhydrolysis to give the bisphenol and potassium chloride, is very slow at100 C. and at 140 C. over 24 hours, since the curves for both thesetemperatures virtually level off with time at the stage of 50% formationof chloride ion.

EXAMPLE 7 The experiments described in Examples 5 and 6 were repeatedusing 1,1-dioxothiolan instead of dimethyl sulphoxide as solvent. Thehydrolysis appeared to proceed more slowly, in spite of vigorousstirring. Two liquid phases were present throughout both experiments.

EXAMPLE 8 Pure bis-(4-chlorophenyl) sulphone (359 g.; 1.25 mole),potassium hydroxide solution (64 g.; containing 5.0 moles of KOH), anddimethyl sulphoxide (2.5 dmfi) were stirred under nitrogen in astainless steel vessel for 5 hours at 100 C. and then poured into water(10 dmfi). The milky solution was acidified with nitric acid and 4 (4chlorophenylsulphonyl)phenol precipitated; analysis of the solution forchloride ion showed 51.3% hydrolysis of the chlorine substituents in thestarting material. The 4-(4-chlorophenylsulphonyl)phenol was extractedinto ether. The other solution was extracted with aqueous sodiumhydroxide (to separate phenolic material from any unhydrolysed startingmaterial), and the sodium hydroxide solution was acidified once again togive 4-(4- chlorophenylsulphonyl)phenol (320 g.; 95.5% yield) M.P.143-145 C., probably contaminated with a little bis-(4-hydroxyphenyl)sulphone. The product was dissolved in hot toluene, in which thebis-phenol is sparingly soluble (about 0.1%), filtered hot and allowedto crystallise. Recrystallisation was carried out from chloroformcontaining active charcoal and yielded a product of MP. 145-146 C. Itwas soluble in cold aqueous potassium hydroxide, sodium carbonate orpotassium carbonate but insoluble in warm aqueous sodium bicarbonate and(like phenol itself) was precipitated from its solution in potassiumhydroxide by carbon dioxide.

The potassium salt was isolated as a yellowish powder, M.P. 274-276 C.,by the reaction of an ethanolic solution of4-(4-chlorophenylsulphonyl)phenol with an equimolar amount of potassiumethoxide (under anhydrous conditions) or of aqueous potassium hydroxide.The salt was soluble in cold dimethyl formarnide, cold dimethylsulphoxide, warm 1,1-dioxothiolan, warm ethanol and hot nitrobenzene.Exposure of the salt to the atmosphere (relative humidity about 50%)resulted in a weight increase of in 90 minutes, corresponding to theforma- 10 tion of a monohydrate, and the colour changed from yellow topure white.

To prepare a polymer, the potassium salt of 4-(4-chlorophenylsulphonyl)phenol (3.07 g.; 0.01 mole) was heated in anevacuated glass tube for 1 hour at 300 C. The tube was cooled and brokenopen. The product was crushed and warmed with dimethyl formarnide (30cmfi), in which potassium chloride is largely insoluble, to dissolve thepolymer. The solution was filtered and poured into water (150 cm?) withvigorous agitation. The precipitate was washed with water and dried togive a colourless polymer (2.2 g.) having a reduced viscosity of 0.60 ina 1% solution in dimethyl formarnide at 25 C.

EXAMPLE 9 Aqueous potassium hydroxide (26.00 g.; containing 0.20 moleKOH) was added to a solution of bis-(4- chlorophenyl) sulphone (28.7 g.;0.1 mole) in dimethyl sulphoxide (200 cmfi) in a stainless steel vessel.The mixture was stirred under nitrogen for 24 hours at C. Water anddimethyl sulphoxide were removed by distillation at about 1 torr whilethe temperature was raised to about 180 C. The last traces of dimethylsulphoxide were removed by crushing the product and heating it at about180 C. for 2 hours at about 10- torr.

The dried solid was heated at 300 C. for 30 minutes in a stainless steelvessel under nitrogen. After cooling, the product was crushed and warmedwith dimethyl formarnide (300 cm?) to dissolve the polymer whilepotassium chloride and a small amount of resin remained undissolved andwere filtered off. The solution was poured into water (1500 cm?) withvigorous agitation. The precipitate was washed with water and dried togive a colourless polymer (16.5 g.) having a reduced viscosity of 0.49in a 1% solution in dimethyl formamide at 25 C.

The polymer was compression-moulded at 320 C. for 5 minutes to give atough transparent film.

EXAMPLE 10 Bis-(4-chlorophenyl) sulphone was hydrolysed as described inExample 9 by aqueous potassium hydroxide in dimethyl sulphoxide over 24hours at 100 C. The solution so obtained was cooled to room temperatureand decanted through a filter to remove potassium chloride: on theassumption that the potassium salt of 4-(4-chlorophenylsulphonyl) phenolhad been produced, this removed 97% of the potassium chloride formed,the rest stayed in solution. The resulting mobile yellow solution wasplaced in a rotary evaporator and the pressure was reduced to below 1torr as the temperature was progressively raised over 8 hours to 240 C.to distil off the dimethyl sulphoxide. The product remaining was ayellow solid containing about 40% of the potassium salt of 4-(4-chlorophenylsulphonyl)phenol, about 60% of a low polymer of reducedviscosity 0.06 (in a 1% solution in dimethyl formarnide at 25 C.), about0.4% of dimethyl sulphoxide, and other substances in low concentration.

This product (11.5 g.) was polymerised at 280 C. for 30 minutes in aglass tube which was continuously evacuated by a high-vacuum pump. Thevolatile substances evolved were collected (0.06 g.) and consisted ofabout 40% water and 60% dimethyl sulphoxide. The solid product from thepolymerisation was crushed and warmed with dimethyl formarnide 100 cmfi)and filtered to remove insoluble material; this was entirely potassiumchloride and no insoluble polymer was present. The solution of polymerin dimethyl formamide was poured with stirring into water (1 dmfi) toprecipitate the polymer, which was washed with water and then withmethanol and dried in vacuum at C. The product (8.6 g.; 99% yield) had areduced viscosity of 0.52 in a 1% solution in dimethyl formarnide at 25C., and gave a strong tough compression moulding.

A similar polymerisation carried out without continuous evacuation (i.e.without continuous removal of dimethyl sulphoxide or some harmfuldecomposition product) yielded a polymer of bad odour and colour and oflower molecular weight but containing up to of polymeric material(probably cross-linked) insoluble in dimethyl formamide.

EXAMPLE 11 Bis-(4-chlorophenyl) sulphone was hydrolysed as described inExample 3 by aqueous potassium hydroxide in dimethyl sulphoxide over 24hours at 100 C. The solution in dimethyl sulphoxide was cooled anddecanted from solid potassium chloride and 1,1-dioxothiolan (35 cm. wasadded. Dimethyl sulphoxide was removed by distillation at 10 torr andsome 1,1-dioxothiolan was also allowed to distil to sweep away the lasttrace of dimethyl sulphoxide. Distillation was continued until theproduct was an 80% w./w. solution of the crude potassium salt of4-(4-chlorophenylsulphonyl)phenol in 1,1- dioxothiolan. When cold, thesolution solidified as a brittle material completely soluble in water.

When this material was heated in nitrogen for 7 hours at 240 C., apolymer was formed having a reduced viscosity of 0.22 (in a 1% solutionin dimethyl formamide at C.) If the material was first diluted with1,1-dioxothiolan to give a concentration of 45%, heating under similarconditions yielded a polymer of reduced viscosity 0.18. In neither casewas any polymer formed insoluble in dimethyl formamide.

EXAMPLE 12 A solution of the potassium salt of4-(4-chlorophenylsulphonyl)phenol in dimethyl sulphoxide was preparedand decanted from potassium chloride as described in Example 10. Most ofthe water and dimethyl sulphoxide were then removed by distillation at25 torr, and when cold the product was powdered and placed in a rotaryevaporator and the temperature was raised to 260 C. while the pressurewas 0.1 torr. The product was a hard brittle prepolymer containing about99% low polymer (reduced viscosity 0.2 at 1% in dimethyl formamide at 25C.) and about 1% of the potassium salt of4-(4-chlorophenylsulphonyl)phenol; the concentration of dimethylsulphoxide was less than 0.1% and probably less than 0.01%.

This prepolymer (5.0 g.) was heated in vacuo for minutes at 280 C. in aglass tube. It was then cooled and dissolved in dimethyl formamide andseparated from potassium chloride which was filtered off. The polymerwas precipitated by adding the solution to water: the product (3.5 g.)had a reduced viscosity of 0.58 g. (in a 1% solution in dimethylformamide at 25 C.), and no polymer was formed insoluble in dimethylformamide.

The prepolymer (5.0 g.), when heated in nitrogen for 30 minutes at 280C. in a glass tube and worked up as before, yielded a polymer (3.6 g.)of reduced viscosity 0.62. No insoluble polymer was formed.

The prepolymer (5.0 g.) and 1,1-dioxothiolan (6.1 g.) were stirredtogether and the temperature was raised to 220 C., when all theprepolymer appeared to have dissolved and the concentration of thesolution was about w./w. Further polymerisation was carried out at 240C. for 4 hours; the solution was cooled and water was added toprecipitate a polymer (3.7 g. after washing and drying) having a reducedviscosity of 0.42.

EXAMPLE 13 Pure bis-(4 chlorophenyl) sulphone (14.36 g.; 0.05 mole),aqueous sodium hydroxide (8.99 g.; 0.10 mole NaOH), and dimethylsulphoxide (100 cm?) were stirred under nitrogen for 24 hours at 100 C.in a stainless steel vessel. A tandem experiment showed that 48.2% ofthe chlorine initially present in the bis-(4-chlorophenyl) sulphone waspresent as chloride anion under these reaction conditions.

Most of the dimethyl sulphoxide and water were removed by distillationat 20 torr, and the product was finally dried in a rotary evaporator ata temperature rising to 270 C. at a pressure of 0.1 torr. The productwas a yellow powder comprising about 20% of very low polymer and aboutof the sodium salt of 4-(4-chlorophenylsulphonyl phenol.

This product (10.02 g.) was heated for 30 minutes at 300 C. in vacuo andworked up as described in Example 10 to give polymer (6.62 g.; 84%yield) of reduced viscosity 0.26 (at 1% in dimethyl formamide at 25 C.).A similar polymerisation carried out at 325 C. gave a polymer (3.81 g.;42% yield) having a reduced viscosity of 0.55, together with a resin(4.20 g.) insoluble in dimethyl formamide.

EXAMPLE 14 Pure 4 (4-chlorophenylsulphonyl)phenol (21.87 g.; 0.10 mole),prepared as described in Example 8, was dissolved in ethanol (50 cm?)and aqueous sodium hydroxide (54.48 g.; 0.10 mole NaOH) Was added. Thesolution was evaporated to dryness at room temperature under reducedpressure and finally dried at 200 C. for 24 hours under high vacuum. Thesodium salt of 4-(4-chlorophenylsulphonyl)phenol was obtained as anofii-white solid of M.P. 320325 C. Titration with 0.1 N hydrochloricacid gave the purity as 99%.

This pure sodium salt (0.962 g.) was heated in vacuo above 325 C. for 30minutes. The product was cooled, dissolved in dimethyl formamide andfiltered to remove undissolved sodium chloride, and the polymer wasprecipitated by adding the solution to methanol. The precipitate waswashed repeatedly with methanol and water and dried at C. in vacuo togive a polymer (0.75 g.; 98% yield) having a reduced viscosity of 0.47in a 1% solution of dimethyl formamide at 25 C.

EXAMPLE 15 4,4'-bis-(4-chlorophenylsulphonyl) biphenyl (10.06 g.; 0.02mole) was stirred with aqueous potassium hydroxide (5.12 g. of 43.7%solution; 0.04 mole KOH) in dimethyl sulphone (75 g.) at under nitrogenin a steel beaker for 92 hours. The solution was concentrated bydistilling dimethyl sulphone (53 g.) under reduced pressure, and themixture was polymerised by stirring under nitrogen at 230 for 17 hours.After the polymerised mixture had cooled to room temperature, it wastreated with dimethyl formamide and a small quantity of insolublematerial was filtered off. The dimethyl formamide solution was pouredslowly into stirred water. A polymer having repeating units of theformula was filtered otf, washed with methanol and dried under vacuum.

EXAMPLE 16 4,4 bis-(4-chlorophenylsulphonyl)-biphenyl (5.03 g.; 0.01mole) and bis-(4-chlorophenyl)sulphone (11.48 g.; 0.04 mole) werestirred with aqueous potassium hydroxide (12.79 g. of 43.7% solution;0.10 mole KOH) in dimethyl sulphoxide (100 cmfi) at 140 C. undernitrogen in a steel beaker. When most of the dimethyl sulphoxide hadbeen distilled off, under reduced pressure, and solid began to come outof solution, dimethyl sulphone (80 g.) was then added and distillationwas continued until dimethyl sulphone (50 g.) had been collected. Themixture was then polymerised at about 230 C. for 18 hours undernitrogen. The reaction mixture was allowed to cool and dissolved indimethyl formamide. The dimethyl formamide solution was poured slowlyinto stirred water, from which the polymer precipitated. Afterfiltration, the creamcoloured polymer was washed with methanol and driedunder vacuum at 100 C. The polymer having repeating units of theformulae -SOz-O (80 mole percent) and -SO2-O (50 mole percent) and (50mole percnt) had a Tg of about 300 C. and could be solvent-cast fromdimethyl formamide.

EXAMPLE l7 1,3-bis-(4-chlorophenylsulphonyl) benzene may be hydrolysedor cohydrolysed and polymerised by the methods of Examples 15 and 16 togive polymers having repeating units of the formula EXAMPLE 181,5-bis-(4-chlorophenylsulphonyl)naphthalene may no hydrolysed orcohydrolysed and polymerised by the methods of Examples 15 and 16 togive polymers having repeating units of the formula 'QJw n In thefollowing examples reduced viscosities were measured at 1% in dimethylformamide at C.

EXAMPLE 19 The potassium salts of 4-(4-chlorophenylsulphonyl) phenol(1.00 g.) and 4-(4-chlorobenzoyl) phenol (1.00 g.) and dimethyl sulphone(2.00 g.) were heated together under dry nitrogen for 18 hours at 220 C.The viscous reaction product was allowed to cool and was then dilutedwith dimethyl formamide. The resulting solution was filtered and thendripped into stirred aqueous methanol (50:50 v./v.) and the polymerwhich precipitated was collected, washed with boiling methanol and thendried in vacuo. The resulting polymer (1.0 g.) contained 7.8% sulphur,corresponding to the structure III/I=52/48, and had reducedviscosity==0.22. The polymer was crystalline (M.P. 295 C.) and wasstable in air up to 500 C.

EXAMPLE 20 Example 19 was repeated using 7.5 g. of dimethyl sulphone.0.8 g. of polymer was obtained with reduced viscosity=0.30.

EXAMPLE 21 The potassium salts of 4-(4-chlorophenylsulphonyl) phenol(1.00 g.) and 4-(4-ch1orobenzoyl) phenol (1.00 g.) and 1,1-dioxothiolan(10.0 cm?) were heated together 14 under dry nitrogen for 4.5 hours at240-250 C. The reaction mixture was allowed to cool and was thenfiltered and dripped into stirred water. The precipitated polymer wascollected, washed with boiling methanol and then dried in vacuo to yield1.8 g. of a crystalline polymer having reduced viscosity=0. l 0.

EXAMPLE 22 The potassium salts of 4-(4-chlorophenylsulphonyl) phenol(1.00 g.) and 4-(4-chlorobenzoyl) phenol (1.00 g.) were heated togetherat 320-340 C. under dry nitrogen for 1 hour. The reaction products wereheated with dichloroacetic acid (40 cmfi) at C. for 30 minutes and theresulting solution was filtered.

The filtrate Was dripped into stirred water and the polymer whichprecipitated was collected, washed with boiling methanol and dried toyield 0.4 g. of an amorphous polymer containing 8.0% sulphur,corresponding to the structure III/I=53/47.

The residue was washed with water and dried to yield 1.6 g. of anamorphous solid.

EXAMPLE 23 The potassium salts of 4 (4 chlorobenzoyl) phenol 1.00 g.)and 2 (4 chlorobenzoyl)pheno1 (1 g.) and dimethyl sulphone (12 g.) wereheated together under dry nitrogen for 18 hours at 220 C. The reactionmixture was allowed to cool and was diluted with hot dimethyl formamide.The resulting solution was filtered and then dripped into stirred water.The polymer which precipitated was collected, washed with hot methanoland dried to yield 0.7 g. of a crystalline polymer having reducedviscosity=0.18.

EXAMPLE 24 The potassium salt of 2-(4-chlorobenzoyl)phenol (1.00 g.) washeated under dry nitrogen at 320340 C. for 1 hour. The reaction productwas worked up as described in Example 22 to yield, from the filtrate,0.2 g. of a highly crystalline polymer (M.P. 290 C.) and, from theresidue, 0.8 g. of a crystalline material. A similar polymerisationcarried out in solution in dimethyl sulphone yielded an amorphousproduct (see Table 1).

EXAMPLE 25 Bis-(4-fiuorophenyl) sulphone (100 g.; 0.394 mole), potassiumhydroxide solution (91.98 g.; 0.787 mole KOH) and dimethyl sulphoxide(400 cm?) were stirred together in a stainless steel vessel undernitrogen at 57 C. for 24 hours. Two liquid phases remained throughoutthe reaction. The reaction mixture was diluted with water and twiceextracted with diethyl ether to recover nonphenolic material (9 g.). Theaqueous phase was then acidified and the phenolic component (86 g.; M.P.154 C.) was extracted with more ether. By subliming this product under adiffusion pump at 0, followed by recrystallisation from toluene (400cm.*), 4-(4-fluoro phenylsulphonyl)phenol (72.5 g.) was obtained, M.P.158-159 C. The potassium salt was obtained from this phenol as a verypale yellow solid.

A little of the potassium salt was melt-polymerized at 280 C. for 30minutes with continuous evacuation. No volatile material was evolved anda tough polymer of very good colour was obtained having a reducedviscosity of 0.95.

The potassium salt (13 g.) was polymerized in 1,1 dioxothiolan (20 g.)for 16 hours at 200 C. The polymer was then end-stopped by adding methylchloride (0.5 g.) in 1,1-dioxothiolan (12 cm?) at 150 C. and the colourimmediately changed from a pale yellow to an almost white slurry. Thesystem was diluted with di' methyl formamide and the polymer (10.5 g.)was repprecipitated with water; it had a reduced viscosity of 0.46 andcompression mouldings made at 320 C. for 3 minutes were tough and ofexcellent colour.

The potassium salt (15 g.) was dissolved in redistilled dimethylsulphoxide (10 cm. The stirred mixture was heated in a glass vesselmaintained at 160 C. for 18 hours under a slow stream of nitrogen. Thepolymer was end-stopped by bubbling methyl chloride into the stirredmixture at 150 C. The colour changed from pale lemon-yellow to whiteover minutes. After minutes dimethyl forrnamide was added and thepolymer was then precipitated with hot distilled water in a macerator.The product was completely soluble in dimethyl formamide and had areduced viscosity of 0.40. Compression mouldings were tough and ofexcellent colour, and the polymer was stable in the melt for 35 minutesat 380 C. (2.3 kp.).

We claim:

1. A method for the production of fiber and film-forming aromaticpolymers whose molecular chains comprise benzenoid groups and oxygenatoms, in which a dihalogenobenzenoid compound having the formula x x Q-Q in which X and X are each a halogen atom and Y is SO;, -SO-, C0, or aradical of the formula Y'A-Y"- in which Y and Y" each is -SOg-, -SO- or--CO-- and A is a bivalent aromatic radical having both valencies linkedto carbon atoms is caused to react with a substantially equivalentamount of an alkali metal hydroxide by the displacement of alkali metalhalide in a polar liquid which is an ionizing solvent for alkali metalphenoxides and is stable under the reaction conditions employed, thereaction being concluded under anhydrous conditions and at a temperaturebetween 150 C., and 350 C.

2. A method according to claim 1, in which the polar liquid is also asolvent for the polymer produced.

3. A method according to claim 1, in which the polar liquid is water ora mixture of water and another liquid or liquids stable to heat underalkaline conditions.

4. A method according to claim 1 in which the dihalogenobenzenoidcompound is a bis-(4-halogenophenyl) sulphone or ketone.

5. A method according to claim 4, in which bis-(4- chlorophenyl)sulphoneis caused to react with potassium or sodium hydroxide.

6. A method according to claim 4 in which an arcmatic polymer isproduced by a reaction which is initially carried out at a temperaturebelow 200 C. in a polar liquid which is an ionising solvent for alkalimetal phenoxides and is stable at the temperature employed, this diluentbeing removed before the polymerization is concluded at a temperatureabove 200 C. in the substantial absence of liquid diluent.

7. A method according to claim 4 in which an aromatic polymer isproduced by a reaction which is initially carried out at a temperaturebelow 200 C. in a polar liquid which is an ionizing solvent for alkalimetal phen oxides and is stable at the temperature employed, and thepolymerization is concluded at a temperature above 200 C. in thepresence of a diluent substantially unreactive under the conditionsemployed.

8. A method according to claim 7 in which said polar liquid is replacedwith another diluent before the polymerization is concluded at atemperature above 200 C.

9. A method according to claim 1 in which abis-(halogenophenyl-sulphonyl) benzenoid compound, alone or togetherwith another dihalogenobenzenoid compound is caused to react with analkali metal hydroxide by the displacement of alkali metal halide.

10. A method according to claim 9 in which the bis-(halogenophenylsulphonyl) benzenoid compound has the formulaX-C5HSOQ-AI'SOQC6H4 X in which X is a halogen atom and Ar is a bivalentaromatic radical derived from benzene, biphenyl, terphenyls, or afused-ring aromatic hydrocarbon containing not more than three aromaticrings.

References Cited The following references, cited by the Examiner, are ofrecord in the patented file of this patent or the original patent.

FOREIGN PATENTS 8/1967 France. 6/1965 France.

OTHER REFERENCES MELVIN GOLDSTEIN, Primary Examiner US. Cl. X.R.

1. A METHOD FOR THE PRODUCTION OF FIBER AND FILM-FORMING AROMATICPOLYMERS WHOSE MOLECULAR CHAINS COMPRISE BENZENOLD GROUPS AND OXYGENATOMS, IN WHCIH A DIHALOGENOBENZENOID COMPOUND HAVING THE FORMULA